The article starts by pointing out that the organizational contract, characterized mainly by its long-term duration and its arrangement in networks, is just as important in practice as are simple exchange contracts. Nonetheless, in contract law doctrinal thinking, legislation, and also comparative law studies, it has received much less attention. In the present essay, the question is asked whether this state of affairs may not be due to the fact, at least in part, that core developments in other social sciences – in this case particularly in institutional economics and in the new economic sociology – have not properly been taken into account. In the first main part of the essay, it is indeed argued that the concept recognized in institutional economics of a relation-specific investment (O. Williamson) could well have been the basis for developing core needs for protection and a regulation satisfying these needs. The second main part of the essay explains that the concept of ongoing reciprocity described in the new economic sociology (W. Powell) as the core characteristic and key to the success of networks can be used as a solid basis for developing legal rules and duties. Thus, the organizational contract does not only seem to be “underrepresented” in legal discourse and legislation as compared with the simple exchange contract. It also casts light on how much law and legal scholarship can benefit from the insights gathered in other social sciences.